Close analysis of the present brake-sent message displayed on the rear-end of vehicles reveals that it has serious problems and needs correction. The message is not complete; it lacks uniformity both in its composition and in its pattern of display on various vehicles; under certain commonly occurring conditions it is even false. These deficiencies cause misinterpretation, not only of its message but also of the message from the other lamps.
In order to understand these problems, it is helpful to consider all the code systems used on the rear-end of vehicles. All of these codes provide information about how a vehicle relates to its path. The message of the presence (tail) lights is primarily that of coution--a vehicle is present on the path. This message is sent by lower, red side-lamps. Since red lamps are not used on the front-end of vehicles, the presence lights include a second message: that the rear-end is being observed.
The turn signals indicate caution--a vehicle is about to converge with or diverge from its path. This message is sent by a flashing bright over-ride through the lower red side-lamps or through separate adjoining yellow lamps. Reverse lights are white lamps intended mainly to make the path visible to the driver for the reverse maneuver. When present on a vehicle, these lights indirectly signal caution, this vehicle may be proceeding in reverse. These lights are not easily visible during daylight, and, thus, unless a red lamp is activated, during adverse conditions, the rear-end presents itself as a front-end proceeding forward.
The remaining messages have to do with path-following. Path-following exists in two major phases: (1) joining the flow (flow-pursuance); (2) resisting the flow (flow-impedance). Flow-impedance consists of four phases: (a) warning prior to slowing, (b) slowing, (c) being stopped, and (d) proceeding in reverse.
The path-following information currently available is limited to what is suggested by the depression of the brake pedal. Depression of the brake pedal will show the intent to slow down as well as the condition of being stopped. More generally stated, this message is caution--you are about to impede the flow of traffic. When the brake pedal is not depressed, the off-condition of the lamp naturally suggests the message opposite of flow-impedance--that the vehicle is joining the flow. This message, however, has a serious problem. When the brake-activated lamp is out, the vehicle is not always joining the flow. Additional observation on the driver's part is then required to confirm the lamp's message: to see what the vehicle is actually doing, that it is really joining the flow, or is slowing, or is stopped.
This arrangement has a deficient message dependent for its clarification on the driver's observation of his surroundings. Such a dependency leads to the message being improperly decoded as driving conditions deteriorate and it becomes more necessary to rely solely on the lamps for information. This happens in traffic jams where drivers almost exclusively focus their attention ahead on the brake generated message. As soon as the lead car's brake light goes out, drivers accelerate forward and then immediately apply their brakes, in panic, when they discover that the lead car has not joined the flow. This same method of decoding is also noticeable in connection with the use of the turn signals, where drivers do not take the turn signals seriously until they see a foot-brake application. This may or may not happen; when it does, it often occurs after considerable engine braking.
In view of the mentioned problems, it has been suggested that an extra central rear red "third" brake warning light be employed on automobiles, especially on the common passenger car. The U.S. Department of Transportation has now mandated a central brake light unit in or at the level of the rear window to be original equipment on all new automobiles sold in the U.S.A. An example of such a light unit is shown in U.S. Pat. No. 4,575,782, issued on March 11, 1986, to Levine, et al.
Others have suggested such a central light, including the present inventor in U.S. Pat. No. 3,364,384, issued on January 16, 1968. That light included provision for signaling deceleration. Other warning light systems are shown in U.S. Pat. Nos. 2,853,572; 3,105,884; 3,320,586; 3,336,450; 3,395,388; 3,414,879; 3,501,742; 3,806,870; 4,034,338; 4,149,141; 4,173,012; 4,224,598; 4,463,411; 4,470,036; 4,600,913; and 4,602,320. See also U.K. Patent 2,028,024 to H. Moffat and West German Patent 3,026,674 to Dietlicher. These units often employ a number of different colored lights for different situations, involving the problem of re-educating drivers in general to their meaning. They also are objected to as being distracting. Often, fears of highways lighting up like Christmas trees are stated as arguments against such systems.
The current Department of Transportation-mandated brake lamp or light, although a step forward in highway safety, does not provide for many common dangerous conditions, and to the extent it becomes accepted, it may well lead to unfortunate over-reliance on it by drivers. For example, if a vehicle equipped with such an extra brake light stops on a highway, the drivers approaching from the rear will see the extra light, only so long as the driver keeps his or her foot on the brake pedal. However, if that same driver decides to back up (an even more dangerous condition for rearward-approaching cars), the rear warning light goes out --a condition that could easily be misinterpreted by an approaching vehicle and result in collision.
All the problems that attend the path-following message, for a system which must use only a single lamp, can be corrected by doing just two things: All vehicles should have a centrally located high-mounted lamp and the message of the lamp should be that, on normal roads, it would be off only when actually joining the flow, no matter what the transmission. This means that it can be on whenever it seriously resists the flow. It would be on in reverse, when stopped; and it could be on for all serious instances of slowing. As an advance warning for lane changing, it would be on flashing steady as prescribed by the position of pedal before slowing. This advance warning also helps interpret the message from the side lamps. Apart from the turn signal use, it would show foot-brake slowing and engine braking as initiated by a foot brake application. After the lamp is on for any of these reasons, it cannot be cancelled until the vehicle accelerates forward, beginning at any speed.
Central to creating this total effect is the correct use of the accelerator. The accelerator must not be made to send any message merely upon its release, which would be to use a deceleration switch. The message sent solely by such a switch over-loads a single lamp with too many activations that do not result in flow-impedance. These extraneous, false message lead to confusion.
The correct use of the accelerator employs, instead, an accelerator switch. This switch will cancel any flow-impedance message only upon depression of the accelerator, and that at any speed whatsoever, thus always having the lamp out whenever joining the flow.
This switch, used only in conjunction with all serious instances of impedance, will produce a simple message that is reliable and, of greatest importance, never false. It will send exactly the same messages that the present lamp sends but more of them. This extra time is not a matter of just being on longer, but rather of being on when needed. Even increased, this time span is still minimal but incorporates all the information required to prevent misinterpretation of both its message and that of the other lamps.